function sys=obv(t,x,ut,Qk)
sys=zeros(3,1);
u1 = 20;u2 = 1;u3 = 1;u4 = 0.01;u5 = 0.01;u6 = 2;
a1 = 3/10;a2 = 3/10;a3 = 3/10;
l1 = 1.7;l2 = 1.7;l3 = 1.7;o3 = 0.5;k = 0.1;

x1=x(1);x2=x(2);x3=x(3);n1=Qk(3);

sys(1)=x2-u1*(x1-n1)^a1-u2*(x1-n1)^l1+14/1805*x1 - 168/9025*x2 + 1/38*x3 - 2/45*(28/361*x1 + 7/95*x2 + x3)+ut;
sys(2)=x3-u3*(x1-n1)^a2-u4*(x1-n1)^l2;
sys(3)=-u5*(x1-n1)^a3-u6*(x1-n1)^l3;